With the iLrn Heinle Learning Center, everything you need to master the skills and concepts of the course is built into this dynamic learning environment. The iLrn Heinle Learning Center includes an audio- and video-enhanced eBook, assignable textbook activities, companion videos with pre- and postviewing activities, partnered voice-recorded activities, an online workbook and lab manual with audio, interactive enrichment activities, and a diagnostic study tool to help you prepare for exams.